Hemostatic clip and delivery system

ABSTRACT

A clipping device includes (a) a shaft defining a lumen therethrough from a proximal end which, during a procedure remains outside the body accessible to a user and a distal end including a distal opening which, during a procedure is inserted into the body to a position adjacent to target tissue; (b) a flexible clip deployable from the distal opening, when in an unconstrained state, the clip assuming a shape selected to clip tissue and prevent a flow of fluid therethrough wherein, while residing within the lumen the clip is held substantially straight by an inner diameter of the lumen; (c) a control wire extending through the lumen from the proximal end to the distal end thereof; and (d) a release mechanism connecting the control wire to the clip during deployment of the clip and disconnecting the control wire from the clip after deployment thereof.

PRIORITY CLAIM

The present application is a Continuation of U.S. patent applicationSer. No. 12/033,449 entitled “Hemostatic Clip and Delivery System,”filed on Feb. 19, 2008, now U.S. Pat. No. 8,845,658; which claims thepriority to the U.S. Provisional Application Ser. No. 60/891,579 filedFeb. 26, 2007. The entire disclosures of these patents/applications areexpressly incorporated herein by reference.

BACKGROUND

Peptic ulcer disease (PUD) is a condition where bleeding occurs from thewalls of the gastro intestinal (GI) tract. A peptic ulcer is an erosionin the lining of the stomach or duodenum. Symptoms vary from patient topatient and may include nausea, heartburn, fatigue, vomiting blood etc.The condition is particularly dangerous in cases where the lesion to thetissue perforates the lining of the stomach or of the intestine,requiring emergency medical attention.

Treatment for PUD consists of hemostasis procedures, where the flow ofblood from the damaged blood vessels is stopped. The procedure may becarried out endoscopically, with thermal therapy, injection ofhemostatic medications, or cautery using lasers and argon plasma. Clipsand other mechanical devices such as the Endoclip™ devices manufacturedby the Olympus Corporation, may also be used to stop the flow of bloodfrom the eroded tissue. Because the location of these hemorrhages areoften deep within the body, deploying hemostatic clips is a complex andtime consuming procedure.

SUMMARY OF THE INVENTION

The present invention is directed to a clipping device comprising ashaft defining a lumen therethrough from a proximal end which, during aprocedure remains outside the body accessible to a user and a distal endincluding a distal opening which, during a procedure is inserted intothe body to a position adjacent to target tissue and a flexible clipdeployable from the distal opening, when in an unconstrained state, theclip assuming a shape selected to clip tissue and prevent a flow offluid therethrough wherein, while residing within the lumen the clip isheld substantially straight by an inner diameter of the lumen incombination with a control wire extending through the lumen from theproximal end to the distal end thereof and a release mechanismconnecting the control wire to the clip during deployment of the clipand disconnecting the control wire from the clip after deploymentthereof.

The invention is further directed to an endoscopic tissue clippingsystem comprising a shaft sized and shaped for insertion through aworking channel of an endoscope and a clip assembly disposable withinthe distal end of the shaft, the clip assembly comprising a plurality ofclips connected to one another by links, each clip being biased toward aclosed position selected to clip tissue and a control wire operativelyconnected to the clip assembly to advance the clip assembly through theclip magazine. The system further includes a heating element disposed onthe distal end of the shaft, the heating element being operable todegrade a selected one of the links to release a distal most one of theclips from the clip assembly and a cam selectively opening the distalmost clip to receive target tissue so that, after passing the cam, theclip moves to the closed position.

In addition, the invention is directed to a method for clipping tissuecomprising advancing a distal end of a flexible shaft to a first desiredposition within the body adjacent to a first portion of target tissue tobe clipped and actuating a control wire extending through the shaft toadvance a clip out of the distal end of the shaft over the first portionof target tissue, the clip being biased toward a tissue clipping shapeselected to grip tissue received therein wherein, when received withinthe shaft, the clip is substantially straight in combination withadvancing the clip out of the delivery shaft so that the clip reverts tothe tissue clipping shape compressing the first portion of target tissuereceived therein and detaching the clip from the control wire.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a diagram of a delivery system for an hemostatic clipaccording to the invention;

FIG. 2 shows a diagram of the delivery system according to the inventionwith a clip being deployed;

FIG. 3 shows a diagram of the delivery system shown in FIG. 2 with theclip fully deployed;

FIG. 4 shows a diagram of a second embodiment of a delivery system foran hemostatic clip according to the invention;

FIG. 5 shows a diagram of a third embodiment of a delivery system for anhemostatic clip according to the invention;

FIG. 6 shows a diagram of a further embodiment of a delivery systemaccording to the present invention, for delivering multiple hemostaticclips; and

FIG. 7 shows a detail of the distal end of the delivery system shown inFIG. 6.

DETAILED DESCRIPTION

The present invention may be further understood with reference to thefollowing description and to the appended drawings, wherein likeelements are referred to with the same reference numerals. The presentinvention relates to hemostasis procedures including endoscopichemostasis procedures. More specifically, the invention relates tosystems and methods for delivering hemostatic clips to the GI tract.However, those skilled in the art will understand that the clipsaccording to the invention may be used for procedures other than thosedirected to hemostasis. For example, the clips may be used to jointissue layers, folds or organs or for grasping tissue for removal orrepositioning. The clips may be rotatable through rotation of a controlwire coupled thereto. Furthermore, the device according to the presentinvention may be used in conjunction with a standard endoscope or mayalternatively include a vision system of its own. Alternatively, thedevice may be configured for use with a specialized endoscope and may bedelivered without direct visualization using other known techniques tolocate the target site as would be understood by those skilled in theart.

The embodiments of the present invention cause hemostasis of bleedingblood vessels in a body lumen (e.g., within the GI tract) using a clipdesigned to stop the flow of blood to an ulcer or to other targettissue. The exemplary clip according to the invention is formed into thedesired shape at the bleeding site, and is not preformed before deliveryto the target site. The resulting delivery mechanism may be made smallerand more flexible than current designs making the delivery device moremaneuverable and user friendly and facilitating delivery of the deliverymechanism and the clips to target sites via an endoscope.

As will be understood by those skilled in the art, the hemostatic clipsystem of the present invention may be used to control GI bleeding aswell as to stop a flow of fluids elsewhere in the body. For example, theinvention may be used to stop bleeding in procedures such as endoscopicmucosal resectomy, bowel perforations, tube ligation closures, etc.Bleeding or other fluid flow located in hard to reach anatomicalcavities may be treated using the device according to the invention.

An exemplary embodiment of the hemostatic clip and delivery systemaccording to the invention is shown in FIG. 1. The hemostasis system 100comprises a delivery sheath or shaft 102, a control wire 104, a releasemechanism 112 and a clip 110. The distal end 114 of the delivery sheath102 is advanced through an endoscope working channel to the targettissue, while a proximal end of the control wire 104 remains accessibleto the operator.

The delivery sheath 102 may be, for example, an hollow shaft similar toa catheter or a flexible biopsy forceps. The outside diameter of thedelivery sheath 102 may be of approximately 0.100 inches or less. Thesmall diameter allows the shaft to rotate freely within the workingchannel of an endoscope during use, to assist in placing the clip 110.The delivery sheath 102 may comprise a working channel 108 extendingtherethrough, to contain the clip 110 and a control wire 104. A distalopening 116 permits deployment of the clip 110 over the target tissue.

In one exemplary embodiment, the delivery sheath 102 may be manufacturedof a plastic such as HDPE, or may comprise a metallic core coated with alubricious outer shell. Alternatively, the delivery sheath 102 may bemanufactured of a braid-reinforced polymer to improve its mechanicalcharacteristics. Those of skill in the art will understand that othermaterials may be used to manufacture the delivery shaft of the presentinvention.

The exemplary control wire 104 may be metallic, and is used to advancethe clip 110 from within the delivery sheath 102. Near the distal end114 the control wire 104 is operatively connected to the clip 110 via arelease mechanism 112, described in greater detail below. The proximalend of the control wire 104 extends beyond the proximal end of thedelivery sheath 102 to connect to an actuating mechanism used by theoperator to release the clip 110.

The release mechanism 112 provides an interface between the control wire104 and the clip 110 forming a mechanical connection to the clip 110while the device is inserted into the body and during the initial stepsof deployment of the clip 110. In the final stages of deployment, therelease mechanism 112 severs the mechanical connection so that the clip110 remains attached to the target tissue and the delivery sheath 102can be withdrawn.

In one exemplary embodiment, the release mechanism 112 comprises aweakened, failure point of the control wire 104 having, for example, across sectional area reduced compared to the rest of the control wire104. An end of the control wire 104, distal from the release mechanism112, may be attached to the clip 110 with conventional means, such aswelding, soldering, heat shrink, etc. When it is necessary to releasethe clip 110 from the control wire 104, force is applied to the releasemechanism 112 to break the mechanical connection. For example, atorsional shear force may be applied through the control wire 104 fromthe proximal end, sufficient to cause the failure point to fail.

In a different embodiment of the release mechanism 112, a polymer orother bonding agent may be used to bond a proximal portion of the coil110 to a distal portion thereof with a torsional shear strength of thepolymer selected to be lower than that of the rest of the control wire104 to define a failure point where the proximal and distal portions arebonded to one another. After a coil 110 has been secured to targettissue, the control wire 104 is twisted by the user imparting to thefailure point a torque shear which, when a predetermined level isexceeded, causes the failure point to yield separating the proximal anddistal portions of the control wire 104 from one another.

In another embodiment, the release mechanism 112 may comprise a fusiblelink coupled to an electrically conductive control wire. The exemplarydelivery system 200 shown in FIG. 4 comprises a delivery sheath 202 witha conductive control wire 204 passing therethrough. A fusible link 212connects the control wire 204 to the clip 210 before deployment iscomplete. When it is desired to separate the clip 210 from the controlwire 204, electric current sufficient to cause failure of the fusiblelink is supplied to the control wire 204 releasing the clip 210 from thecontrol wire 204. For example, as would be understood by those skilledin the art, the capacitance of the fusible link 212 may be selected tobe less than that of the control wire 204 so that, when electric currentis applied to the control wire 204 from the power source 220, thefusible link 212 melts or breaks severing the bond between the controlwire 204 and the clip 210.

The exemplary delivery system 100 shown in FIG. 1 also includes a clip110 comprising, for example, a coil which returns to a desired shapeafter deformation. As would be understood by those skilled in the art,the coil forming the clip 110 may be made from a preformed metallic wire150, or from any other material having the desired mechanical andelastic properties. In its natural, unconstrained state the wire 150 hasthe shape of a loop, as shown by clips 110 and 210 in FIGS. 3 and 4.When the coil 110 is assembled within the delivery sheath 102, the shapeof the working channel 108 forces it into a substantially straightshape, as shown in FIG. 1. Thus, when inside the delivery sheath 102,the coil 110 appears as a substantially straight wire.

Once the target tissue is reached, the coil 110 is advanced by thecontrol wire 104 through the opening 116, such that the constrainingforce is removed. The coil 110 then takes its natural, unrestricted loopshape, and coils around the target tissue to compress it andmechanically cause hemostasis. This condition is shown in FIG. 3. Thoseof skill in the art will understand that various materials may be usedto manufacture the coil 110. For example, shape memory alloys or othermaterials that are capable of assuming a desired shape in response tochanges in external conditions may be used. Any materials or coatingsthat strengthen the clip without adding large amounts of material andincreasing the cross sectional dimension of the clip may be used.

An alternative embodiment of the hemostatic clip according to theinvention is shown in FIG. 5. In this embodiment, the clip 260 of thedelivery system 250 has an operative shape resembling the letter “V”,similar to the shape of a surgical clip or an aneurysm clip. Prior todeployment, the clip 260 is contained within the deployment sheath 252in the shape of a substantially straight wire. When the control wire 254pushes it out, the clip 260 returns to the unconstrained “V” shapeconfiguration, with legs 262, 264 joined at a sharp bend. The clip 260is placed over the target tissue before returning to the unconstrainedshape, so that the release mechanism 256 can detach the clip and leaveit on the target tissue.

An exemplary mode of use of the hemostatic clip deployment system isdescribed with reference to FIGS. 1-3. The preliminary steps ofintubating the patient, insufflating and locating the bleeding site withan endoscope are carried out. The delivery device 100 is introduced intothe scope and is advanced to the site, in proximity of the target tissue122. Specifically, the distal tip of the delivery sheath 102 is placedagainst an ulcer 124 or other opening to be closed (e.g., woundsresulting from biopsies, polyp removal, etc.). The procedure may becontrolled visually by the physician using the vision equipment of anendoscope.

The control wire 104 is advanced through the working channel 108, thusadvancing the coil 110 out of the opening 116 of the delivery sheath 102and onto the ulcer 124. Under direct visualization, the clip 110continues to be advanced and, as it leaves the delivery sheath 102, itforms a tightening coil 120 around the ulcer 124. The base of the ulcer124 is compressed, stopping the flow of blood to the wound. When thecoil 120 is fully formed, the physician twists the control wire 104 tobreak the release mechanism 112. Twisting the control wire 104 may alsoplastically deform the coil 120, applying additional force to the lesionaiding in establishing hemostasis. The delivery sheath 102 may then bewithdrawn while leaving the clip 110 coiled around the ulcer 124.

In many cases the ulcer is large, and more than one clip may benecessary to completely close the wound and stop the hemorrhage. Placingmultiple clips on the target tissue may be difficult with a single clipdevice, because it is necessary to remove the device, load an additionalclip and advance the device again to the correct site of the lesion todeploy the new clip. Multi-clip devices may be used, which storemultiple clips and are able to deploy them on the lesion without needingto remove, reload and reintroduce the device to target site.

Embodiments of the present invention provide for a multi-clip deliverydevice to cause hemostasis of hemorrhaging blood vessels that aredifficult to reach. In particular, the treatment of bleeding occurringalong the GI tract such as peptic ulcers may be treated by deployingmultiple clips with the invention, which may be delivered to the targetsite of the bleeding with an endoscope.

In one embodiment, the invention comprises a multi clip device whichincorporates fusible links used to connect multiple links withsufficient structural integrity while the device is still able to flexwhen advanced through a working channel of the endoscope. The fusiblelinks allow the clips to be released and deployed one at a time over thetarget tissue. According to the invention, the multiple clips are linkedin series using semi-rigid fusible links. The links and the clips form asemi rigid clip assembly that allows the chain of clips and thedeployment device to maintain flexibility and be able to advance througha tortuous path.

When the operator wants to deploy one of the clips, a mechanism isactivated to sever the fusible link between the two most distal clips inthe clip assembly. For example, localized heat may be applied to themost distal link in the chain. The heat causes the fusible link todegrade rapidly until the most distal link is free from the chain. Atthis point the next most distal clip in the series is ready to bedeployed using the same procedure, after the distal end of the device isre-positioned over the target tissue.

One exemplary embodiment of the multi clip device according to theinvention is shown in FIGS. 6 and 7. The device comprises clips 310,fusible links 308, an actuation wire 320, a heating mechanism 312, adelivery shaft 302 and a power supply interface 326. The distal end ofthe delivery shaft 302 defines a hollow magazine 304 that contains theclip assembly 306 formed of the clips 310 connected by the fusible links308.

The clips 310 of the exemplary device are designed to be in a closedposition in a resting state, when unaffected by external forces orconstraints. The clips 310 may comprise a pair of legs 330 formed from acontinuous strip of metal. Opposing jaws 332 may be formed at the endsof the legs 330, capable of compressing the target tissue around thehemostasis site. Since the clips are closed in their natural state, amechanism is provided to open the clips during deployment, to allowtissue purchase. One exemplary opening mechanism actuates the clip 330to the open position prior to deployment by forcing the clip's legs 332to track over pins 350 in the distal end of the delivery shaft 302. Thepins 350 act like cams, directing the movement of the legs 332.

Those of skill in the art will understand that the clips 310 may havedifferent geometry that what is shown in the drawings. For example,multi legged clips may be used, and clips that are made of non metallicmaterials. The device may use clips that are naturally open, and thatare closed by a closure mechanism of the delivery shaft 302. Forexample, pins or cams analogous to those described above may be used toclose the clips over the target tissue, and a conventional lockingmechanism of the clips may be used to retain the legs 332 in the closedposition. One such lock includes a ring which may be slid distally overa clip 310 preventing the legs 332 from moving radially outward towardthe open position.

The fusible links 308 connect pairs of successive links 310. The links308 may be formed of a polymer that allows them to be overmolded ontothe proximal end of one clip 310 and the distal end of an adjacent clip310. The links 310 have a certain amount of flexibility, so that theclip assembly 306 does not become too stiff and prevents the distal endof the delivery shaft 302 from passing through a tortuous path. Thefusible links 308 have sufficient compressive strength to allow theseries of clips in the clip assembly 306 to be pushed by the actuationwire 320, during advancement of the clips 310 and deployment of the mostdistal clip 314. As would be understood by those skilled in the art, thefusible links 308 need not be formed as solid members. Rather, theselinks 308 may be formed as coiled, spring like structures with open orclosed surfaces (i.e., with adjacent sections of the coil touching oneanother or separated longitudinally from one another).

When it is necessary to detach the most distal clip 314 form theadjacent clip 310, the distal fusible link 316 is degraded usinglocalized heating. As the heat is applied to the link 316, it separatesfrom the distal end of the clip 310, located next to the clip 314 beingdeployed. In this embodiment, the link 316 remains attached to theproximal end of the most distal clip 314 that is deployed, to preventbeing lost in the operative area. The link 316 may be manufactured of anelectrically conductive plastic, or may comprise a conductive element todirect the heating to a desired portion near the more proximal clip.

In different embodiments, other materials may be used to manufacture thefusible links 308. For example, the links may be metallic, or may beformed of an electroactive polymer so that less heat may be necessary todeploy the clip 310. In the latter embodiment, warm water from thelavage feature of the endoscope may be used instead of a dedicatedheating system to release the clip. Instead of degrading the material ofthe link, using an electroactive polymer would require reshaping thematerial of the link.

Another embodiment of the link 308 may be manufactured by includingelements of shape memory alloys. For example, the link 308 may beconstrained to one shape that forms a connection to the clips 310 whilewithin the delivery shaft 302. Once the link 308 is advanced past aselected point at the end of the delivery shaft 302, the constraint isno longer present, and the clip 308 is free to return to itsunconstrained, memory state. The memory state may be such that one ofthe clips 310 attached to the link 308 is released, so that it may bedeployed.

In the exemplary embodiment described, the heating mechanism 312comprises an electrical circuit receiving power form a power supply viaan interface 326, which may be a conventional connector. The electricalpower is routed to the fusible link 316 by conductive elements, suchthat the link 316 is destroyed because of the heating generated. Abipolar or a monopolar power supply may be used according to theinvention, depending on requirements of the procedure.

According to a further embodiment of the invention, the heatingmechanism 312 may be used to direct some heat to the clip 310. Anadditional therapeutic benefit may be obtained by heating the clip 310,because the hemorrhaging target tissue may be cauterized as well asbeing mechanically compressed by the clip 310. This aspect of thetherapy is beneficial, because cauterization is a preferred method oftreatment for peptic ulcer disease.

The actuation wire 320 may be a metallic control wire similar to thatdescribed above, having a proximal end actuated from outside the body byan operator using a slide 322 and handle 324 or other type ofconventional actuating mechanism as would be understood by those skilledin the art. The actuating mechanism according to this embodiment ispreferably designed such that the clips 310 are released by placing thecontrol wire 320 in either compression or tension to push or pull theclips distally, respectively. The control wire 320 is preferablymanufactured of an electrically non-conductive material, to keep itinsulated from the electrical energy powering the heating mechanism 312.

The delivery shaft 302 according to the invention comprises a flexiblemetallic coil, similar to the shafts used in biopsy forceps devices. Inan exemplary embodiment, the shaft 302 may be coated with a layer offlexible, lubricous material to facilitate insertion through the workingchannel of an endoscope and minimize the potential for damage to theendoscope. The coating may also be electrically insulative, to protectthe operator and the patient from inadvertent electrical shock. In adifferent embodiment, the shaft 302 may be formed entirely from anelectrically non-conductive material with a separate conductive elementcarrying electrical power to the heating element 312. Alternatively,other heating elements suitable for use with the present invention mayinclude sources of laser energy, ultrasound, RF, etc.

After a patient has been intubated and prepared for the procedure, thedelivery shaft 302 is advanced and the power supply is connected to thepower supply interface 326. The distal end of the device is theninserted into the body to a desired position adjacent to target tissue(e.g., a site of internal bleeding caused by an ulcer), so that the clip310 may be deployed on the target tissue.

The user manipulates the actuation wire 320 to advance the clip assembly306 relative to the shaft 302 and to open the most distal clip 314 inclose proximity to the target tissue. Further manipulation of theactuation wire 320 causes the clip 314 to close over the target tissue.At this point, the heating mechanism 312 is energized to release theclip 314 as the link 316 is destroyed. The clip 314 remains locked inposition over the target tissue while the delivery device 300 is freedfor removal and/or repositioning over a subsequent portion of targettissue. The procedure is repeated to clip other portions of the targettissue as necessary.

The present invention has been described with reference to specificexemplary embodiments. Those skilled in the art will understand thatchanges may be made in details, particularly in matters of shape, size,material and arrangement of parts. Accordingly, various modificationsand changes may be made to the embodiments. The specifications anddrawings are, therefore, to be regarded in an illustrative rather than arestrictive sense.

What is claimed is:
 1. An endoscopic tissue clipping system, comprising:a shaft sized and shaped for insertion through a working channel of anendoscope; a clip assembly disposable within a distal end of the shaft,the clip assembly comprising: a plurality of clips connected to oneanother by links, each clip being biased toward a closed positionselected to clip tissue; a control wire operatively connected to theclip assembly to advance the clip assembly through the clip magazine; anenergy delivery element disposed on the distal end of the shaft, theenergy delivery element being operable to degrade a selected one of thelinks to release a distal most one of the clips from the clip assembly;and a cam selectively opening the distal most clip to receive targettissue so that, after passing the cam, the clip moves to the closedposition.
 2. The system according to claim 1, further comprising: apower supply providing energy to the energy delivery element.
 3. Thesystem according to claim 1, further comprising: a hand operated controlactuating the control wire.
 4. The system according to claim 1, wherein,in an unconstrained state, each of the clips reverts to a substantially“V” shape with legs biased toward a tissue gripping position in whichthe legs close against one another to grip tissue received therebetween.5. The system according to claim 4, wherein the cam is shaped to openthe legs of a distal most one of the clips upon a predetermined amountof actuation of the control wire and, after reaching a maximum openstate, to allow the distal most one of the clips to revert to the tissuegripping position.
 6. The system according to claim 1, wherein theenergy delivery element includes a heating element.
 7. The systemaccording to claim 6, wherein the links comprise polymer links couplingeach of the clips to the control wire, each of the links beingdegradable when heated to release the corresponding clip when the linkis heated by the heating element.
 8. The system according to claim 7,wherein each link degrades when heated to release the corresponding clipfrom a more proximal clip.
 9. The system according to claim 1, whereinthe energy delivery element includes one of a source of laser energy,ultrasound energy and RF energy.
 10. The system according to claim 1,wherein each of the links has a stiffness selected to retain a desiredcolumn strength and bending flexibility of the clip assembly.